Display sign



July 25, 1944. 0, FORD 2,354,367 DISPLAY SIGN Fil'ed vFeb. 26, 1940ATTORNEY Patented July 25, 1944 UNITED STATES. PATENT, OFFICE 2,354,361

tion February 261344111311 neszwzs 19 Claims.

The invention relates in general to a sign or other illluminated articleand specifically relates to a combined light transmitting and signcharacter providing element of a sign formed of thermoplastic materialand to a method of producing thus an important object of the inventionis toprovide a form of sign which can be economically operated.

Another object of the invention is to provide for what may be called acold light sign or 11- luminating device and thus permit theinstallation of a sign or illuminating device in places where it wouldnot be convenient or desirable to have a source of-light as in arefrigerator or compartment containing combustibles and which sign canbe illuminated from a remote or otherwiseconvenient location outside ofthe limits of the sign proper and outside of the space illuminatedthereby. Such form of device, of course, requires the use of some formof light transmitting element and the present disclosure particularlyrelates to the providing of an improved form of such light transmittingelement which can be easily constructed to disclose any desired signcharacter or symbol.

The invention has for another object the providing of a signin which thesign characters can be readily replaced in case of damage or to formdifferent words and in the invention herein disclosed this is mosteasily obtained 'by the use of readily replaceable light transmittingelements each one of which is provided with its own sign character.

The present disclosure accordingly features a light transmitting /lementfor a sign which can be conveniently assembled with other similar lighttransmitting elements each forming a sign character or each providedwith its own sign character formed thereon as a permanent part thereof.It has been sug e ted that this light transmitting element be formed ofglass, quartz and like transparent materials but it has been founddimcult, if not impossible, to form such materials into sign charactersor to form the necessary sign characters on such hard frangible materialwhich transparent material identified as methyl-methacrylate orequivalent polymerized derivative 01' methacrylic acid and marketedunder the trademark designation of Lucite. This particular material hasbeen specifically selected due to its optic characteristics and to thefact that it can be readily machined or bent to shape particularly undercertain circumstances.

Various other objects and advantages of the invention will be in partobvious from an inspection .of the accompanying drawing and in part willbe. more fully set forth in the following par-.

ticular description of one form of apparatus embodying the invention,and the invention also 'consists in certain new and novel features ofconstruction and combination of parts hereinafter set forth andclaimed.

In the accompanying drawing:

Fig. 1 is a fragmentary view in side elevation of one of the combinedlight transmitting and signcharacter forming elements and showing an endview of another similar element shown associated with a source of lightand constituting a preferred embodiment of the invention;

Fi 2 is a transverse sectional view taken on the line 2-2 of Fig. 1looking in the direction indicated by the arrows;

Fig. 3 is a view in front elevation of another form of sign illustratinganother embodiment of the invention with part of the sign face brokenaway to show the normally hidden parts of a set of elements and a sourceof light;

Fig. 4 is a vertical'transverse sectional view taken on the line 4-4 ofFig. 3;

Fig. 5 is another embodiment of the invention in the form of threebulb-like members shown for the most part in horizontal section andgrouped about a single source of light;

Fig. 6 is a detailed transverse sectional view of one of the bulb-likeelements and taken on the line 6-6 of Fig. 5;

Fig. '7 is an elevational view of a sign character bent to shape, shownassociated with two two are shown extending at right angles to eachother, one of which marked I l is shown in front elevation and the othermarked I2 is shown in end elevation. It is suggested that the completesign comprise four such rods or bars extending radial y from the lightsource it. These bars or rods are of similar construction so thedetailed description of one will suillce for any number grouped aboutthe source Ill. The bar is of substantially cylindrical form and isformed from a bar of methyl-methacrylate initially having a highlypolished outer surface.

The rear side of the bar, that is, the side opposite the side facing theobserver is formed with a flat face l5 which is machined as hereinafterdescribed to form thereon a plurality of sign characters It. Formingthese characters on the rear side so that they are visible through theopposite rounded side causes them to appear slightly magnified and witha brilliant lustre. For the purpose of showing that the bar may beprovided with decorative effects other than sign characters, there isdisclosed a groove l8 adjacent the light induction end IQ of the bar,which end faces the light source Ill. The bar may be formed of twolengths of material with a screen or divider 20 positioned between thetwo halves and the two parts cemented or otherwise secured together tohold the screen in place. This screen is a layer of a colored materialsuch as Cellophane but may be more or less opaque. In those cases wherethe screen 20 is opaque, it is suggested that another source of light belocated at the left end of the bar, that is, the end opposite the end I!so as to illuminate the portion of the bar to the left of the screen.

The sign characters I are formed by cutting operations, preferably on abar of methyl-methacrylate, the outer surface of which bar is initiallysmooth and preferably provided with a glasssmooth or polished finish. Inperforming this operation, the bar is heated to a temperature above 190F. and is preferably positioned in a bath of boiling water, and thusexposed to a temperature of approximately 212 F. for a short period oftime and at least until the surface to be treated has somewhat softenedto a depth of approximately one-sixth of an inch. Care is exercised notto extend the heating step for a time duration which would cause theblank bar to lose its initial configuration or to cause the surface tobecome so soft that it could not be cut. While this step of heating thesurface is not absolutely necessary to form the best type of areadesired, it has been found that a better effect is created and thesurface responds more readily to the cutting operation by preheating thesame than is the case when such preheating or surface softening is notemployed. The surfaces are machined, cut or drilled preferably by theuse of a high speed steel tool. It is suggested that an improved eifectis created if the cutting tool be dull. In the usual process ofmachining nitro-' cellulose plastics and in urea-formaldehydeandphenol-formaldehyde resins, care is exercised to use high speed andlubricants to avoid chatter marks. 0n the contrary, in practicing thecutting operation as herein described no such care is exercised, nolubricants are used and every effort is made to produce chatter marksand equivalent rough effects as such eflects tend to create a diffusionof the light rays out of their paths. The cutting operation extendsbelow the surface for an appreciable distance so that the resultingcharacters may be said to be embedded in the material rather than simplyscratched or sanded surfaces. This cutting action is not a surfacetreatment but is a distinct deep rough cutting operation which causesthe slightly plastic surface engaged by the cutting tool to become gummywith a resulting whitish or silver-like translucent area. As far as canbe ascertained. this rough cutting of the surface especially whenslightly soft develops a multitude of irregularly shaped and angularlydisposed facets which catch the light rays passing through the bar,reflecting the same outwardly while diffusing the rays with the resultthat the sign character such as ll when so formed shines prominently instrong contrast with the balance of the surface and provides a signcharacter which can be seen for a relatively long distance when takinginto consideration the relatively small amount of light discharged fromthe source Ill.

After the blank has been so machined, it is permitted to cool slowly toatmospheric temperature after which it will permanently retain itsmachined shape. In operation it will be understood that the light raysfrom the source ll passing axially through the several rods II and I2will be reflected by the small facets forming the several signcharacters I4 and diffused in such way that the sign characters willshow up as white areas brilliantly illuminated. Where the light passesthrough a colored screen, the

areas will, of course, take the color of the screen.

Referring to the form of the invention disclosed in Figs. 3 and 4, thereis shown a sign hav ing an opaque front face 2! provided with a line ofapertures 22 of which five are shown in Fig. 3 to receive the signcharacters forming the word Shoes." A source of light 23 is located inrear of the face 2i and preferably in an out-ofthe-way position.

Located between the light source 23 and the apertures 22 are livecombined light transmission and sign character providing elements 24.-

These elements are of similar construction except for diflerences inangle between the opposite ends thereof and different sign characters,[0 the detailed description of one will be sufficient for any of theother ones.

The several elements 24 are each provided with a light induction end 25of relatively small cross-sectional area so that the several ends can begrouped closely in a circular arrangement about and in close proximityto the light source 23. The elements 24 are demountably secured to theface 2| each by means of a metal clamp 26 engaging the element at itsmidlength. The upper end of each of the elements is enlarged to afunnel-shaped or'conical form and the enlarged end of each element isintruded through one of the openings 22. These elements are solid formsof methyl-methacrylate initially cast to form or bent to shape whenfirst softened in a hot water bath. It is appreciated from viewing Fig.3 that the elements which form the end characters of the sign. in thiscase the end 8's of the word "Shoes" are bent more sharply than themiddle 0" character and in general it will be understood that eachelement is bent to best fit the location in which it is intended to beused. A rubber gasket or washer 20 is used to mount each element 24 inits associated opening 22-and to seal the Joint therebetween from lightfiltering therethrough. It is suggested that an opaque sleeve 29,preferably of rubber, enclose the exposed side of the element 24 toavoid light leakage laterally out of the same.

A thin transparent or translucent circular disc of Celluloid orequivalent material with the desired sign character corresponding tothat shown at 30 in Fig. 3 printed or otherwise impressed thereon maybe-removably held in place by a metal clamp 3| having spring fingers 32which engage against the receding conical side of the enlarged end tohold the disc 30 in place.

In operation, it will be understood that thelight from source 23 passesaxiallythrough the several light transmitting elements to illuminateitsassociated'character, in this case the word Shoes," which showsbrilliant white or silverstroked letters with difused light and actingto form a pleasing effect.

Referring to the form of the invention shown in Fig. 5, there isdisclosed a frame 33 supported from a base 34 and provided with a sourceof light 35. Positioned in advance of the source'of light is a pluralityof bulb-like light transmitting elements of which three differentspecific forms are shown at 36, 31 and 38 and each formed ofmethyl-methacrylate. It is understood, of course, that usually only oneform of such elements will be used at any one time. These elements aresupported from the frame by brackets and are preferably so arranged thatthe elements supported thereby may be readily replaced to change thesign display.

These elements may be free of any sign characters thereon and so formspots of light utilized in their particular grouping to form wordssimply by virtue of their relative arrangement.

Referring first to the elements 36 at the left of Fig. 5, there isdisclosed a bulb-like body with an end 40 of reduced cross-sectionalarea facing the source of light and located with its axis extending in aradially directed position so that the light is caused to pass axiallyinto the end of reduced diameter and outwardly through the opposite end4i of enlarged hemispherical form. In this case, the element is providedcentrally thereof with'a hollow space 42 leaving a wall 43 between thehollow space 42 and the outer highly polished surface 44 of the element.The inner surface 45 of this wall 43 has been cut to form the facettedor roughened surface as described in detail for the formation of'theexternal characters l4 in Fig. 1, before the two halves of the characterhave been cemented or welded together. It is further suggested that thisinner surface 45 be silvered wholly or in part or painted with somesubstance to give color to the interior of" the element.

.Referring to the central element 31, it willbe noted that it is of asimilar bulb-shaped form as shown at 36 and is formed of three preformed0on5 rays from the source -35 impinging upon the end ii of reducedcross-sectional area of element 31 will be reflected by the severaljointure surfaces so that the light is diffused outwardly anddownwardly, as indicated by the several arrows, and in all directionsabout the element. The effect produced is that the entire element 31 isluminous.

Referring to the form of element 38 at the right of Fig. 5, there isdisclosed another bulb like element initially molded of two halves cc.-mented together along the jointure line 52. This element is providedinteriorally thereof with .a pair of intersecting grooves 53 and 54, thewalls 55 of some of which are roughened following the a methodhereinbefore described to form the roughened or light reflectingsurfaces forming the characters l4 and 28.

With reference to the operation of the device in so far as this form ofelement is concerned, it will beunderstood that the light rays impingingon the reduced end 56 of the element 3! tends to pass freely and axiallyalong the intersecting grooves and these light rays being caught by theroughened surface 55 are deflected and diffused so that the entireelement takes on a' brilliant whitish or silvered appearance.

' Referring to the form of the invention disclosed in Figs. '7 and 8,there is disclosed a sign character 60, in this cas shown to be a solidbar of methyl-methacrylate bent to the form of an R, constituting one ofa series of such characters arranged with a plurality of similarcharacters constituting letters coacting to form a complete sign.

These sign characters fill are intended to be demountably held in placeon the sign support by a mounting shown symbolically by the clamp I andmore particularly disclosed in my pending application, Serial No.274,643 flied May 19, 1939,

In. this case both ends of the R are exposed to receive light from twosources 62 and 83 but usually one light source is all that is necessaryto illuminate such a sign character.

The element Bil was initially a straight cyiindri cal bar ofmethyl-methacrylate, as commercially produced Lucite." While stillstraight it was placed in a bath of hot water, preferably boiling water(212 F.) until the surface was slightly soft without effecting therigidity of the bar as 'a whole. v

The bar with its surface so softened was in-T sorted in a millingmachine, with a dull milling tool and one side of the soft surface cutmore or less deeply toform a half moon shaped groove or, depression 64extending as far as desired along the length of the rear side of thebar. The faceof the groove 64 is in turn grooved with a plurality ofrelatively small V-shaped grooves 65, the surface of which is roughenedas shown at 66, to form a cut facetted area on the rear side of thefinished character. This produces a whitish back-. ground which givesthe impression that the trans parent letter is formed of a milk whitesubstance. The bar is then reheated, preferably by leaving. it in a hotwater bath for a longer time than was necessary for the surfacesoftening as above described but at a less temperature, for example,about 1'75 E. and until the entire bar becomes; bendabl without breakingor cracking. The bar so softened is carefully bent to fit a suitablemoldor templet, such for example, as a mold for forming the R of Fig. 7,care being exercised to locate; the grooved side rearwardly of the frontor for: wardly exposed face of the character. Lucite'f,

has been found a'particularly suitable material for use in forming suchcharacters as it can be readily bent to shape when slightly softened andlends itself to being shaped to form letters and similar signcharacters, even those with relatively sharp bends in the succeedingstrokes of the letter.

In operation, it will be understood that light from each source H or 63or both pass into the adjacent end or ends of the character. The lightrays are caught by the multitude of facets formed incidental to therough grooving of the rear side of the character and are reflectedtoward the front or exposed side of the character with incidentaldiffusion of the light giving the entire element a soft white, opaleflect.

In any of these forms of the invention illustrated, the indicated sourceof light may be a neon, argon or similar luminescent gas tube so that itis possible by using "Lucite elements to provide a neon" sign aselements ramifying from a single active neon tube.

By constructing a sign as herein suggested and, of course, using a whitelight at th source, it is possible to obtain the equivalent of a neonsign in the production of a soft-non-glare light with the additionaladvantage that the sign will show with a white light in place of theusual colored light characterizing present forms of neon lights.

The invention has been described particularly in connection with the useof polymethyl-methacrylate, a colorless resin, as it produces high lighttransmission with crystal clear transparency but it is within the scopeof the disclosure to utilize a form of Lucite or equivalent form ofthermoplastic material of either the soft or hard grades and whichcontains dyestuffs and pigments capable of producing brillianttransparent and translucent tints adding to the effectiveness of thesign display.

It is also suggested that particles of foreign bodies capable ofreflecting light be either em-' bedded in the surface of the bar whilesoft to give the desired sign characters, or diffused throughout theinterior of the bar in the process of molding the bar to shape as in thecase of the Pig. 7 disclosure.

These particles may be cracked pieces of a hard grade of Lucite mixedwith the molding powder of a softer grade, or they may be formed ofglass or other crystals mixed into the powder before molding. It is alsosuggested that moist air be forced under pressure through the moltenmass of Lucite" to form air pockets or bubbles in the molded article soas to give the desired internal light reflection and diffusion.

I claim:

1,. In the art of preparing a light transmitting sign element, themethod which consists in heating a blank formed of a polymerizedderivative 5' of methacrylic acid to about 212 F. to soften a surfacearea of the blank and raggedly cutting a sign character 01 desired forminto said soft surface area for an appreciable depth to form a roughenedarea beneath the level of the surface capable of disclosing the signcharacter as a whitish area when light is passed through the blankparallel to said cut surface.

2. In the art of forming a light transmitting sign element, the methodwhich consists in sub- Jecting a blank of polymerized derivative ofmethacrylic acid to the heating effect of boiling water for a period oftime sufllcient to soften one of its exposed surfaces without changingthe initial configuration of the body and drilling, grooving orsimilarly machining said soft surface with roughened areas to formtherein a desired form of sign character having a silver-like reflectingsurface comprising a multitude of angularly disposed facets capable ofreflecting light passed through the blank parallel to said surface.

3. In the art of preparing an article from a transparent body ofmethyl-methacrylate, the method which consists in heating the bodysumcient to soften one of its faces without affecting the originalconfiguration of the body, machining said face while soft with a dulltool to cut therein a translucent area formed of a multitude ofgummy-like angularly disposed facets and permitting the cut body to coolto atmospheric temperature.

4. The method which consists in heating a body of methyl-methacrylatehaving a highly polished surface to a temperature of approximately 212F. and machine cutting a design into a portion of said polished surfacewhile at such temperature.

5. In the art of forming sign characters, the method which consists insurface heating a bar of methyl-methacrylate, subjecting one side of theheated bar to the action of a dull tool of a high speed milling machineoperating under conditions to form in the surface grooves havin chattermarks and bending the grooved bar while so into the shape desired.

6. In a sign, the combination of an elongated light transmitting elementformed of methylmethacrylate, with one surface having a translucent areawith tool markings thereon, said element being otherwise transparent,and a light sourc for directing a ray of light through said element, andagainst said tool markings in said translucent area to cause the lightrays to be reflected by the tool markings to show a sign character.

7. A body of methyl-methacrylate having a translucent area of prescribedform in one face thereof and within the outlines of said face and thebalance of the body being transparent, said translucent area beinglocated a material distance below the surface of the transparent faceand forming a multitude of minute light reflecting facets disposed at amultitude of angles to the general plane of the translucent area andmeans for directing light rays through the body and on to said minutereflecting facets to be diffusedly reflected therefrom.

8. An element of a sign comprising a cylindrical bar constructed of apolymerized derivative of methacrylic acid having a sign characterformed in a rear face thereof and extending for a material distancebelow the surface of said face in distinction from being merely aroughening of the surface of said face and the front face of said barbeing highly polished the strokes forming said sign characters beingeach formed primarily of a flat layer of irregularly shaped andangularly disposed facets, said sign characters being slightly magnifiedwhen viewed through the rounded front polished face of the bar.

9. A sign including a sign face provided with a plurality of openings, aplurality of solid light transmitting elements one for each opening andeach having an end of enlarged cross-sectional area protruding throughone of the openings, and provided with a sign character at its enlargedexposed end, the opposite end being of relatively small cross-sectionalarea whereby a large number of said small ends may be grouped closelytogether about a point, said sign characters coacting to form a word, asingle source of light at said point in rear of the sign face anddisposed to direct light into the ends of the elements of smallcross-section opposite the enlarged end whereby the sign elements areilluminated from a single light source.

10. A light transmitting element of bulb-like form constructed from apolymerized derivative of methacrylic acid and having a light receivingend of small cross-sectional area and a light dis charging end ofrelatively large cross-sectional area, the exterior surface of saidelement being smooth and -having within its outline and thus spaced fromits exterior surface, a roughened surface capable of reflecting anddiffusing light as it passes through the element from end to end outthrough said smooth exterior surface.

11. A light transmitting element constructed from a polymerizedderivative of methacrylic acid having a recess within its outlinesoutlined by a plurality of relatively fiat walls, and otherwise solidand a source of light for directing light through the element andthrough said recess, at least one wall ofsaid recess having thereonmachine markings to render the same translucent to diffuse the lightpassing through the same.

12. A light transmitting element having its exterior surface smooth andprovided with an interior recess and otherwise solid, said recess beingoutlined by a wall, at least a-portion of which is silvered.

13. A bar-like length of methyl-methacrylate bent to form a signcharacter and having a machined face constituting a three dimensionalmeans-for reflecting light laterally out of the character andincidentally diffusing light rays passing longitudinally through thebar-like length.

14. A luminous sign including a translucent element composed of methylmethacrylate resin fashioned to disclose a display character, a sourceof illumination to illuminate and irradiate said display character and acolored transparent member carried by said element and placed betweensaid source and said display character to irradiate said color throughthat portion of said translucent element beyond said screen.

15. A luminous sign comprising a casing, a plurality of translucenthollow elements composed of methyl methacrylate resin and having theirbases secured to said casing, said translucent elements scored on theinside to reflect light from a source of illumination, and a source ofillumination in the casing and external to said elements for irradiatingthe same.

16. A luminous sign comprising a casing, a plurality of translucentelements each composed of methyl methacrylate resin and certain of saidelements having an angled form in which one part extends at an angle toanother part, means for mounting the elements in the casing to locate apart of each exteriorally of the casing and a part intruded within thecasing, the parts of the elements exterior of the casing provided withlight reflecting parts and a single source of iilumination in the casingfacing the intruded ends of the elements to irradiate said lightreflectin parts.

17. A sign element formed entirely of methyl methacrylate resin forminga connected arrange-- ment of strokes and bends shaped to form a displaycharacter, with one end forming a light induction and straight strokeforming and adapted to be exposed to a source of illumination and meansfor mounting the element in place.

18. A sign element formed entirely of methyl methacrylate resin anddisplaying a sign character, one side of said element provided with agroove in turn grooved with a plurality of relative small groovesforming a whitish field visible through the front face of the element.

19. In the art of forming a sign character, the method which includesthe step of forcing air under pressure through a molten mass oftransparent methyl-methacrylate to form light refleeting air pockets orbubbles therein and molding the resulting molten mass into a desiredform of homogeneous material.

DAVID OTIS F0

